The present invention relates generally to trainline communications and more specifically, to the serialization of cars in a train.
With the addition of electro-pneumatically operated train brakes to railway freight cars comes a need to be able to automatically determine the order of the individual cars in the train. In an EP brake system utilizing a neuron chip or other "intelligent circuitry" a wealth of information is available about the status of each car in the train, but unless the location of the car in the train is known, the information is of little value. It has been suggested that each car report in at power-up. While this will provide information on which cars are in the train consist, it does not provide their location in the consist. Present systems address this issue by requiring that the order of the cars in the train be manually entered into a data file in the locomotive controller. While this does provide the information necessary to properly locate each car in the train, it is very time consuming when dealing with long trains, and must be manually updated every time the train make-up changes (i.e. when cars are dropped off or picked up). The proposed system eliminates the need for manually entering this data by providing the information necessary for the controller to automatically determine the location of each car and EP control module or node in the train.
Historically, there has only been a communication link between one or more of the locomotives in a train with more than one locomotive needed. Current EP systems require a communication link between all cars and locomotives in a train or consist. The Association of American Railroads has selected as a communication architecture for EP systems LONWORKS designed by Echelon. Each car will include a NEURON chip as a communication node in the current design. A beacon is provided in the locomotive and the last car or end of train device to provide controls and transmission from both ends of the train.
The serialization of locomotives in a consist is well known as described in U.S. Pat. No. 4,702,291 to Engle. As each locomotive is connected, it logs in an appropriate sequence. If cars are connected in a unit train as contemplated by the Engle patent, the relationship of the cars are well known at forming the consist and do not change. In most of the freight traffic, the cars in the consist are continuously changed as well as the locomotives or number of locomotives. Thus, serialization must be performed more than once.
Thus, it is an object of the present invention to provide an automatic method of serializing the cars in a train having communication nodes at each car.
Another object of the present invention is to provide a method for each node on a train to determine where it is within the train consist.
These and other objects are achieved by providing a parameter which varies along the length of the train and transmitting a synchronization signal along the length of the train to the local nodes at each car. The parameter is measured at each node with respect to the occurrence of the synchronization signal at the node. Serialization of the cars is then performed as a function of the measured parameters.
One method is to provide the parameters by transmitting a second or serial signal which propagates through the train at a slower rate than the synchronization signal and then measuring the difference in time between the receipt of the synchronization and the serial signal at each node. The synchronization and the serial signal may be transmitted in any order with one beginning the time period and the other ending the time period. This information is used for the serialization. The synchronization and serial signal may be transmitted through two different mediums, for example, the synchronization signal could be an electric signal and the second signal could be a fluid signal transmitted through a brake pipe. The serial signal may be transmitted by a transmitter and the cars moving relative to each other to serially actuate a receiver on each car.
A second method of implementation is to create a pressure gradient in the brake pipe along the length of the train. The brake pipe pressure is read at each node upon receipt of the synchronization signal. The pressure gradient can be created during charging or a pneumatic braking command or resulting from a leak. The measuring of brake pipe pressure can be measured directly at the brake pipe or at a reservoir being charged by the brake pipe. As a further alternative, the flow rate of a charging brake pipe may be measured at each node.
As a third alternative, an electric load is provided at each node in parallel to a trainline running through the train. This creates a current differential along the trainline. The current or voltage of the trainline at each node is then measured upon receipt of the synchronization signal.
Each node measures the parameter at its node and transmits the measurements with an identifier on the network for synchronization. The locomotive determines the position of each node and transmits the node position to the respective node. Also, each node may determine the position of the node relative to the other nodes using the transmitted measurement. The individual nodes compare its measured parameter to the other measured parameters to determine its relative position. This may be achieved by using a first counter for counting the number of node measured parameters transmitted which are either greater or less than the node measured parameter and a second counter for counting the number of node measured parameters. A comparison of the counter in the first counter to the second counter determines the relative position of the node to the total consist.